Conventionally, in an image display device such as a projector device, when a video image is displayed and a user adjusts the video image to a desired video image, a video image before being subjected to an adjustment and a video image used for the adjustment are displayed so that they can be compared, and then a result of the adjustment made to the video image used for the adjustment is reflected on the displayed video image as corrected data.
Among techniques related to such a video image adjustment is the video image correction system disclosed in Patent Document 1. FIG. 11 is a diagram showing a display screen of the video image correction system disclosed in Patent Document 1.
As shown in the figure, as a means to perform a color correction and noise removal on the screen, two screens that are a reference window RW and a task window WW are displayed in a row. While the two screens are compared, a correction is performed using an operation tool bar TB. In performing the correction, an image to be subjected to the correction is displayed on the task window WW, and data derived from a proper frame relevant to the image is pasted onto the reference window RW.
In the above-described manner, an adjustment of a video image can be performed by a simple operation that is easily understandable to a user, and a correction of instability in terms of a position and a color also can be performed easily.    Patent Document 1: JP2002-262218 A